Metal detectors are first created and introduced in the year 1960. During this time, its main purpose is to help miners and treasure hunters to identify treasures and other metallic objects that are hidden underneath the ground or water. However, over time, this device has gone beyond being just a treasure hunting kit and toll. Nowadays, it is already used by various individuals and establishments for different reasons and purposes.
Recently, metal detectors are perceived to be a tool in helping protect the lives of people. This is also applicable for properties and other things. This practice started pervading after some terrorist attacks that happened years ago, People become more conscious about their protection that they are already making use of every possible device that they can use so that they can ensure their safety and security.
The pervasiveness of metal detectors is evident through the presence of walkthrough detectors in mall and building entrances. Even private schools and institutions are already placing this same device in their entrances. This is to make sure that harmful object such as knives and guns will not enter their premises unnoticed at the same time, guards are already equipped with hand-held detectors so that they can roam around the vicinity and check car parks and other premises of their area.
Other than for the protection of lives and properties, there are also other industries and activities that still use metal detectors. An example for this is the food processing industry. During the food processing method of different sectors, the clash between metals cannot be avoided. Because of this, the tendency that the food will contain metals is a possibility. This is the reason why food industries are also making use of metal detectors. This industry is using this device so that metals would be eliminated from the processed food and that people will not suffer from any food poisoning experience brought upon by metals contained in such products.
Another industry that greatly uses metal detectors is mining and treasure hunting. As mentioned earlier, this is the basic industry that makes use of metal detectors because of the great ease that the tool can provide to them. Because of this same industry, variations to the original model of the detector have also been improved to offer more benefits. An example for this is the creation of metal detectors that can identify the depth of a metallic object and the disparity of the kind of metal that has been detected. Because of this, treasure hunting and mining have become easier for miners and treasure hunters.
Of course, these are not the only uses of metal detectors in this present time. lndustries such as textiles, chemicals, packaging, pharmaceuticals, and plastic industries are also making use of this same device. Of course, they have their uses and purposes for it. Even as an individual, you may consider having your metal detector for leisure purposes. You may use such whenever you want to search the ground for some old coins. This can already be a good hobby for you.
Metal detectors are being used by different establishments and individuals nowadays. Because of its prominence, various types of sensors have already been created. Here are the three basic kinds of detectors based on the technology that it is employing:
Very Low Frequency (VLF)
The Very Low Frequency (VLF) type of technology for metal detectors is the device that is composed of two sets of coils. Each of these sets is comprised of the transmitter coil and the receiver coil. The term “very low frequency” is associated with the receiver coil.
The transmitter coil is the part of the VLF metal detector that is the one responsible for the detection of the metallic objects underneath the ground or somewhere else. The transmitter coil sends the alternating current that later produces the magnetic field upon contact with a metallic object. This is the part of the VLF metal detectors that is responsible for the push and pull movement of the device to the ground upon detection of the metallic object.
On the other hand, the receiver coil still does the same action as the transmitter coil. However, it does not have the same intensity. Instead, this part is using a very low-frequency current and magnetic field. After detection, it transmits the electric current and magnetic waves to the control box. The control box, then, will identify the kind of metallic object that is being detected and how deep it is on the ground.
Pulse Induction (PI)
The technology of pulse induction (PI), on the other hand, is called as such because of the sudden burst or pulse that is created by the device. This kind of metal detector is composed of a single coil with a transmitter and receiver. At times, it may also be composed of 2 or 3 coils.
The mechanism involved in this kind technology is the production of current burst. The device produces a short pulse that is being transmitted to the coil. This, in return, generates the short magnetic field. In every explosion and generation of the magnetic field, the magnetic field reverses polarity. This will eventually collapse and will create an electrical spike. This process then creates the reflected pulse that is necessary for the identification of a metallic object.
Beat Frequency Oscillator (BFO)
The metal detectors that make use of the technology of beat frequency oscillator or BFO are similar in VLF detectors in a way that it uses two coils. The first coil in this kind of detector is found in the search head while the other coil is in the control box. The difference this device has compared to VLF detectors is the mechanism that it employs.
BFO detectors are those that make use of radio waves. The oscillator of this kind of device produces thousands of electric pulses when used. The coil in the search head receives these pulses and converts it into radio waves. The radio wave frequencies are then submitted to the control box where it produces a clear tone. The tone changes when the detector interacts with a metallic object due to the magnetic field that has been created through the interaction of electric current and magnet. This is the reason why the device would be able to detect a metallic object.